When a user is exercising, the watch or band can move, which causes the PPG signal to be very noisy. The algorithm on the MAX32664 uses accelerometer data to suppress the noisy PPG signal motion frequencies; however, sometimes the heart rate output can still be inaccurate.
Three reasons that can the algorithm cannot output accurate heart rate are the following:
1. PPG signal is too weak.
2. The accelerometer signal is not good
3 PPG and accelerometer are not well synchronized